Findings on endocrine disrupters inconclusive Japan

Main Category: Public Health
Article Date: 02 Jun 2004 - 20:00 PDT


The Japanese Environment Ministry is to publish interim findings that show it was unable to confirm the effects on mammals of endocrine disrupters, which are believed to have a negative effect in the reproduction mechanism of animals.

The findings, which are to be released in a pamphlet, show that in tests using river water containing trace elements of two chemicals, including nonylphenol, which is used as an industrial solvent, a sex change phenomenon in the male sperm of a medaka, or Japanese killifish, was confirmed.

"We must be very cautious and think about the effects on the entire ecosystem," a ministry spokesman said.

The test used rats to represent mammals and medaka to represent fish.

The researchers concluded that if tributyltine, diethyl phthalate, or 17 other chemicals believed to have a major endocrine disrupting effect, were found in food or water at levels used in the test, there would be a negative effect on reproduction and behavior of animals in the area.

Nonylphenol and 4 octylphenol were found to bring about a sex change in the medaka, which was not confirmed in the rats.

In an epidemiological survey conducted in the Kanto region and other areas in which endocrine disrupters were thought to have brought about a change in the proportion of births of men and women, no connection or change was confirmed.

In 1998, the ministry listed 67 chemicals as possibly containing endocrine disrupters.

Concern over endocrine disrupters has deepened, so the ministry has begun evaluating chemicals that can be tested and will release the results of tests of the first 19 chemicals in the pamphlet.

Copyright 2004 The Yomiuri Shimbun

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